Optical signals used in high speed circuits and systems such as telecommunication typically are transmitted over long distance in fiber optic cables. However, on an integrated circuit these signals travel in interconnections called optical waveguides. Optical waveguides in integrated circuits are formed as cores surrounded by cladding layers on a substrate for the purpose of transmitting selected modes of optical radiation. The index of refraction of the core is, for at least one polarization in at least one direction, greater than the index of refraction for materials adjacent to the waveguide core, typically called cladding. This difference in index of refraction keeps the light traveling within the optical waveguide due to total internal reflection.
High speed communication systems require optical components that are high speed with low absorption and scattering loss of the optical signal traveling in the optical waveguide. Optical waveguides in integrated circuits fall into two general categories, those using organic and those using inorganic glass core materials and cladding. Inorganic glass waveguides such as SiO.sub.2 have proven to be capable of extremely low loss, while organic waveguides offer simplified fabrication and electro-optic capability but typically without the lower loss of inorganics.
Chen et. al. discloses two polymer on glass waveguide switches in SPIE Vol. 1794, Integrated Optical Circuits II (1992), p. 388-396. The first is a X-branch channel glass waveguide with a strip of nonlinear polymer core on the center top of a "two-mode" region. The second is an asymmetric Y-branch glass waveguide with a strip of non-linear polymer on the top of one branch. These circuits confine the light energy primarily to the polymer core, in contrast to the present invention where the polymer is used as an active cladding. In addition, both are all-optical switches, that is they are activated by changes in the optical power of the signal. All-optical switches provide high speed switching but are limited to those designs where signal intensity can be modulated to control the switch. The present invention includes embodiments of all-optical switches and optoelectric switches.